In the known methods for packaging and/or palletizing piece goods, such as packages, bundles, or the like, these are first conveyed on transport devices conveying in lines, and are shifted, aligned, and/or assembled in a suitable manner for producing desired layer patterns that can be subsequently stacked in multiple layers on top of each other, for example on pallets prepared for this purpose. These treatment steps can be particularly useful in facilities for treating beverage containers. The piece goods in question can be, for example, packages, crates, cartons, bundles, or clusters. For the mentioned pallets to be safe for transport, the assembled layer patterns, which are also referred to as assembled cycles, have to meet certain requirements. In order to form such cycles, it is customarily necessary to perform preparatory procedures, which consist, for instance, in first conveying piece goods regularly or stepwise on a so-called dosing belt, in then grouping or gathering them on an intermediate transport belt, and in delivering them together and/or in groups from there to a layer-forming belt or a layer-forming table.
In the prior art it is known to deliver spaced-apart piece goods from a dosing belt onto a transport belt, which means that in each instance individual piece goods are delivered to the transport belt. This delivery can be carried out by each individual piece good being individually delivered onto the transport belt by way of a velocity difference between dosing belt and transport belt; a control by optical sensors, for example light barriers, can additionally be in place. It is likewise conceivable to deliver the piece goods in a spaced-apart manner from the transport belt by way of operating the layer-forming belt in a stepwise manner. In order to deliver in each instance individual piece goods from the transport belt onto the layer-forming belt in such a manner, the layer-forming belt can be operated in steps that are synchronized with the transport belt by exactly one length of a piece good in transport direction. These cycles or groups or parts of grouped piece goods can also be rotated on the transport belt according to the desired layer pattern in order to then be delivered to the layer-forming belt.
Prior art knows different embodiment variants for designing grouping tables that serve to bring together piece goods, such as cartons, shrink packs, trays, and plastic crates. Piece goods can be brought together by being assembled into a two-dimensional formation (block construction, e.g. pallet layer), for example. For this purpose, a roller conveyor, for instance, can be supplied linearly from one or several lanes. According to requirements, the piece goods can be rotated prior to or on the roller conveyor, and they can be arranged in the required positions mechanically by stop points. The piece goods positioned in such a way can then be pushed off from the roller conveyor in a direction orthogonal to the transport direction. Supplying, arranging, and pushing off the piece goods can in this context be regarded as a cycle. At least one cycle is needed to assemble one layer, normally, however, a plurality of cycles are needed. The partly discontinuous conveyance with its relatively abrupt speed changes or direction changes causes accordingly high mechanical stress on the piece goods, which is possibly detrimental to product-protective processing of the piece goods.
Document EP 1 456 101 A2 discloses an apparatus for forming rows from packaging goods for bundle palletizers. The bundle palletizer comprises at least one layer station and at least one palletizing station. The row forming apparatus comprises at least one positioning station, on which the packaging goods are arranged at desired spaces in at least one row during the transport. The positioning station connects to a staging conveyor associated with the layer station. At least one accumulating conveyor is disposed upstream from the positioning station, which has several conveyor sections arranged consecutively in transport direction with controllable and regulatable drives. The controllable and regulatable drives make it possible to achieve the desired spacing for the packaging goods. The row forming apparatus has at least one monitoring device for identifying and monitoring the spacing of the packaging goods. The construction of this known row forming apparatus is rather elaborate and complicated, especially since many belts are required for forming the spaces and/or for rotating the packaging goods.
An apparatus is known from U.S. Pat. No. 5,123,231 A for assembling articles into groups and subsequently packaging them. On a feeder belt and in each instance with a predefined space, the articles are fed to a collection belt where the groups are assembled from an unvarying number of articles. The groups are then fed to a subsequent belt of a packaging device.
EP 1 927 559 A1 discloses a grouping table for bringing together bundles, in particular shrink packs, for the purpose of forming layers, the grouping table comprising a continuously drivable conveyor, disposed downstream therefrom a cyclically drivable step conveyor, disposed laterally next thereto a layer-forming station, and a push-off device associated with the step conveyor and acting orthogonal to the conveying direction for the groupwise transfer of the bundles onto the layer-forming station.
US 2005/0246056 A1 discloses a system for arranging packaging items into a layer that is deposited or stacked on a pallet in following handling procedures. The system involves three linearly arranged conveyor belts. Via a first conveyor belt, the packaging items are supplied to the apparatus. The packaging items are disposed linearly on the first conveyor belt. With the second conveyor belt, the packaging items are spaced apart. Subsequently, the packaging items reach a third conveyor belt, where the arrangement of the packaging items is carried out. All three conveyor belts run at different, however, in each instance constant speeds. When a layer is completely assembled, it is transferred onto the pallet.
The known prior art as illustrated by different documents can have various disadvantages in practice. The particular velocity differences and high acceleration ramps and/or correspondingly steep deceleration ramps involve the risk that spacing apart or transferring the piece goods between dosing belt, transport belt, and also layer-forming belt cannot be carried out in the intended precise manner. Individual piece goods may even veer off or turn or rotate away from their specified positions. Moreover, the frictional resistance between the particular conveyor belt or transport belt and the underside of the particular piece good also plays a role that is not to be neglected, as it can lead to the spaces between the cycles not being precisely reproducible and thus turning out different. In addition, the distance that the individual spaces need to cover for the so-called procedure of cycling-in from the dosing belt onto the transport belt can result in loss of performance. All of these effects increase the time required for putting together a pallet.
In order to avoid these disadvantages, EP 2 107 018 A1 proposes a method and an apparatus intended for staging cycles of bundles and/or bundle groups safely, quickly, and at top quality, so that the rows for the layers of a pallet can be put together in an effective manner. The proposed apparatus serves for assembling and aligning bundle groups, and it comprises a dosing belt, a transport belt, and a belt for forming rows or layers. The dosing belt, the transport belt, and the belt for forming rows or layers are each provided with an own motor as a drive. The speed of the dosing belt is regulated by a control such that the bundles or bundle groups being transported one batch next to the other can be divided into a number of cycles of bundles or bundle groups on the transport belt. Predefined spaces are formed between the individual cycles. The belt for forming rows or layers can have a robot associated with it, which can shift and/or rotate the incoming cycles from the transport belt to form layers in or transversely to transport direction. In addition, the layer-forming belt is intended to enable the formation of a layer made from a plurality of rows.
Furthermore, a method for forming palletizable layers from piece goods standing next to each other on a layer-forming station is known from DE 10 2011 080 812 A1. Associated with the layer-forming station is a program-controlled manipulator for collecting and/or transferring individual or several piece goods from at least two feed stations that are spatially apart or offset from one another and for positioning the piece goods by rotating and/or shifting them into specifiable release positions on the layer-forming station.
Manipulators of this type or also robots associated with the layer-forming belts can be designed as multi-axis robots, for example, such as are known from DE 10 2009 026 220 A1, for instance, in the context of grouping articles or beverage containers. A frequently used variant of suchlike manipulators are so-called gantry robots, which are often employed in a modular structure in packaging lines, in grouping units, or in palletizing stations. A conveyor belt extending horizontally in longitudinal direction of the conveying level, or a different endlessly circulating means, are types of frequently used transport means or conveying units, on which the objects and/or packages are disposed in predetermined or in randomly assumed positions. Such a module is known, for example, from DE 10 2009 043 970 A1. The gantry robots that are typically employed in such modules, as known, for instance, from DE 10 2010 020 847 A1, can be equipped with gripping apparatuses, for example, for lateral seizing of the piece goods to be handled or manipulated.
It is the primary object of all known handling systems to enable precise positioning of piece goods, packages, bundles, and/or articles for, as far as possible, failure-free and reliable preparation for layer forming, palletizing, and/or packaging. A secondary object that is, however, becoming increasingly important, lies in reducing the cycle times in this process without reducing the already achieved degree of precision and without having to accept decreases in terms of the reliability already achieved. The method is intended to enable processing of piece goods that are conveyed or transported in at least one row. The method is moreover intended to run at a higher speed than has been hitherto possible without creating disadvantages in terms of piece good positioning precision and/or manipulation reliability. The corresponding apparatus is intended to operate faster than the manipulation apparatuses known from prior art and at the same time with at least approximately the same reliability and approximately the same positioning precision.
These objects of the invention are achieved by the subject matter of the independent claims, that is, by a method and an apparatus for handling piece goods moved one after another, the method and the apparatus comprising the features of the independent claims. Features of advantageous further developments of the invention are indicated in the relevant dependent claims.